Fluid-structure interactions in light water reactor systems

A report is given on the First International Seminar on Fluid-Structure Interaction in Light Water Reactors which took place in Berlin, August 20-21, 1979 in conjunction with the 5th International Conference on Structural Mechanics in Reactor Technology (SmiRT). The seminar focused on the pressurized water reactor loss of coolant accident and the boiling water reactor suppression pool analysis. After a general description of these events, the discussion concentrated on the importance of various phenomena, appropriate computational methods and experiments. The PWR event was shown to require very fine spatial resolution for local convergence, particularly at the inlet nozzle. The inclusion of nonlinear fluid behavior, (two phase flow) and nonlinear structural behavior (nonlinear supports and plasticity) in refined models is a current difficulty. Several examples showed the importance of coupled fluid-structure computations. Numerous techniques were presented for BWR suppression pool analyses, most based on incompressible flow. Good agreement was reported with available experiments. The open problems appear to be not the treatment of the interactions, but validated, effective methods for the fluid and structure, although the coupled nature of the calculations requires efficiency in each part. Thus, the development of faster methods and validation by experiments is crucial. (orig.)